nested macro definition

例句：

1. 1. The tree is nestled in the forest with its branches reaching out to touch the sky.
   这棵树在森林里，它的树枝伸向天空。
2. 2.The network is nested within a larger system, making it difficult to understand without context.
   这个网络被更大的系统所包含，没有上下文就很难理解。
3. 3. The city is nestled between two rivers, providing a picturesque backdrop for tourism.
   这座城市位于两条河流之间，为旅游业提供了一个美丽的背景。